noun

1. 1. any thin, flat piece of metal, wood, etc., with a picture, design in relief, etc., hung as on a wall for ornamentation
   2. a wall tablet inscribed to commemorate an event, identify a building, etc.
2. a platelike brooch worn as a badge or ornament
3. 1. an abnormal patch on the skin, mucous membrane, etc.
   2. a thin, transparent film on a tooth surface, containing mucin, bacteria, etc.: if not removed it forms tartar and promotes tooth decay
   3. a deposit of fatty or fibrous material in a blood vessel wall

Etymology: Fr < MDu placke, disk, spot, patch